We have ongoing issues with dealing with backwards compatibility with other parts of the company, contractors, and vendors.
For example, we could not upgrade to Creo 2.0 until our downstream internal customers upgraded as they use and modify our models.
You can hand over a STEP file, but that kind of makes the sharing a single direction path. If any changes come back you have to figure out what was done and re-do them in the original model. You can use Granite, but it's not always quite so easy and you're limited to only a limited number of versions that you can open.
It would be nice is the same Unite Technology "wrapper" used for NX, CATIA, Solidworks, etc. files, where other CAD models can be opened and used within Creo without exporting /importing step files or other such conversions, could also be used for backwards compatibility of Creo models.
That way in the future if the downstream user was still on Creo 3.0 and we were on say Creo 4.0 they would just see our model as a featureless "wrapped" solid but we could continue to update all the features in our Creo 4.0 sessions, and happily move to Creo 5.0, 6.0.... as our needs adjust without breaking the model connectivity. They could also at some point decide to downgrade the model and use direct methods if such a need existed the same as using a STEP file.
This is going to especially become important as Creo updates it's versions on a more regular basis and companies will be stuck behind the slowest adopter. I think it would be in PTC's best interest to enable this kind of functionality as most companies want to upgrade but can't because you can't always push these kinds of changes downstream (upstream?). You'd also think it would be easier for PTC to implement this over other vendor's models.
I'm sure the technology of using the ATB is similar, but it should be more streamlined and not having to copy over files from the newer versions.
This could also extend into Creo Elements Direct and other Creo based Products as well.